JP3850577B2

JP3850577B2 - Charging device

Info

Publication number: JP3850577B2
Application number: JP07373699A
Authority: JP
Inventors: 雅史門永; 貴彦徳増; 健治杉浦; 真小夫; 雅之平野
Original assignee: Hamamatsu Photonics KK; Ricoh Co Ltd
Current assignee: Hamamatsu Photonics KK; Ricoh Co Ltd
Priority date: 1999-03-18
Filing date: 1999-03-18
Publication date: 2006-11-29
Anticipated expiration: 2019-03-18
Also published as: JP2000267398A

Description

【０００１】
【発明の属する技術分野】
本発明は、複写機、ファクシミリ、プリンタ等の電子写真技術を利用した画像形成装置の帯電ユニットに応用される帯電装置に係り、特に静電潜像担持体等の被帯電体を非接触で均一に帯電するための帯電装置に関する。
【０００２】
【従来の技術】
電子写真技術を利用した複写機、ファクシミリ、プリンタ等における作像プロセスでは、静電潜像担持体である感光体上を帯電させるプロセスが存在する。この帯電プロセスとしては、従来は非接触で帯電安定性にも優れているコロナチャージャーによって行われていたが、この方式ではオゾンが多く発生するため、最近では接触帯電方式が検討されており、例えば、特開昭６３−１４９６６９号公報に開示されているような接触帯電方法（導電性ローラを用いたローラ帯電方式であり、ＤＣ電圧にＡＣ電圧を重畳させて導電性ローラに印加する方法）や、特開平６−１７５４６９号公報に開示されているようなブラシ帯電装置（導電性ブラシを用いたブラシ帯電方式であり、導電性ブラシと芯金の間に低抵抗の中間導電部材を設けて、帯電の環境依存性を無くし、被帯電物を一定に帯電させる）が実用化されてきている。
【０００３】
しかし接触帯電方式では、帯電部材が感光体等の静電潜像担持体に接触しているために帯電部材がトナーなどで汚れやすく、その結果、帯電ムラ等の帯電性能の劣化が生じてしまう。
以上のことから、オゾンレスの非接触帯電方式が帯電手段としては理想的であると言える。
【０００４】
そこで本発明者らは先に、電磁波照射装置と電界形成手段を備え、電磁波照射装置により静電潜像担持体上の空間に電磁波を照射すると共に電界形成手段で電界を形成することによって、静電潜像担持体を所望の電位に帯電させる帯電装置を提案した（特開平９−２１８５６１号、特開平９−３２５５７９号）。
この帯電装置では、電磁波照射装置と静電潜像担持体の間にグリッド電極を設けて電界を制御し、電磁波と電界を適宜に作用させることで、電磁波によって生成されたイオンを効率よく静電潜像担持体に付着させて静電潜像担持体を非接触帯電させることができ、帯電の信頼性を向上させることができ、帯電ムラの少ない均一帯電が可能となる。
【０００５】
【発明が解決しようとする課題】
しかしながら、先願の帯電装置では、電磁波照射装置と電界制御用のグリッド電極の距離が振動や経時において変化すると、静電潜像担持体の帯電電位が変動するという問題がある。特にグリッド電極は、通常多数の開口部を持った薄い平板や網状の電極のため、電界や振動によって電磁波照射装置や静電潜像担持体からの距離が変動しやすく、帯電電位にばらつきが生じ易い。また、電磁波照射装置とグリッド電極の組立て時の位置決め制御に手間がかかるという問題がある。
【０００６】
本発明は上記事情に鑑みなされたものであって、電磁波照射装置と電界形成手段を備え、電磁波照射装置により被帯電体上の空間に電磁波を照射すると共に電界形成手段で電界を形成することによって、被帯電体を所望の電位に帯電させる方式の、オゾンレスの非接触帯電方式の帯電装置において、電界制御用の電極と電磁波照射装置間の距離を一定に保つことによって安定した帯電電位を得ることを課題
（目的）としている。以下に本発明が解決しようとする課題を列挙する。
【０００７】
（１）：電磁波照射装置と電界制御電極間距離を一定に制御することによって、電磁波照射装置と電極間の電界強度を常に一定に保つことができ、振動や経時においても安定した帯電電位を確保することを課題とする。また電磁波照射装置と電界制御電極を一体化することで、組み立て時の位置決め制御を簡略化することを課題とする。
（２）：（１）の課題に加え、電磁波照射装置と電界制御電極間での電位差を一定に保ち、短絡を防止することを課題とする。
（３）：（１）または（２）の課題に加え、電磁波により生成されたイオンを確実に被帯電体に移動させることを課題とする。
（４）：（１），（２）または（３）の課題に加え、電磁波照射装置と電界制御電極間距離を一定に制御するための手段の必要最小限の設置位置を規定して装置の簡素化を図ることを課題とする。
（５）：（１），（２）または（３）の課題に加え、電磁波照射装置と電界制御電極間距離を確実に一定に制御するための手段の設置位置を規定すると共に電磁波の遮蔽を図ることを課題とする。
（６）：（１）〜（５）のいずれかの課題に加え、被帯電体の広範囲を一度に帯電させることができる構成を提供することを課題とする。
（７）：（６）の課題に加え、配線の簡略化、装置のアレー化を行い、組み付け工程の簡素化を図ることを課題とし、さらに、電磁波遮蔽効果を向上させ、安全性を確保することを課題とする。
（８）：（６）または（７）の課題に加え、電磁波遮蔽効果をさらに向上させ、安全性を確保することを課題とする。
（９）：（１）〜（８）のいずれかの課題に加え、電磁波の外部への漏洩を確実に防止し、装置の安全性を向上することを課題とする。
【０００８】
【課題を解決するための手段】
上述の課題を解決するための第１の手段は、電磁波照射装置と電界形成手段を備え、該電磁波照射装置により被帯電体上の空間に電磁波を照射すると共に前記電界形成手段で電界を形成することによって、前記被帯電体を所望の電位Ｖｓに帯電させる帯電装置において、前記電磁波照射装置と前記被帯電体の間に電界制御電極を配設して電界を制御すると共に、前記電磁波照射装置と電界制御電極間に空隙制御部材を設けて一体化し、電磁波照射装置と電界制御電極間距離を一定に制御する構成としたものである。これにより電磁波照射装置と電界制御電極間距離を一定に制御することが可能となり、電磁波照射装置と電極間の電界強度を常に一定に保つことができる。また電磁波照射装置と電界制御電極を空隙制御部材を設けて一体化することで、組み立て時の位置決め制御を簡略化することが可能となる。
【０００９】
第２の手段は、第１の手段の帯電装置において、空隙制御部材を絶縁体で構成したものである。このように空隙制御部材を絶縁体で構成すれば、電磁波照射装置と電界制御電極間での電位差を一定に保ち、短絡を防止することが可能となる。
【００１０】
第３の手段は、第１または第２の手段の帯電装置において、電界制御電極を、多数の開部を有するグリッド形状としたものである。このように電界制御電極を多数の開口部を有するグリッド形状とすれば、電磁波により生成されたイオンを確実に被帯電体に移動させることが可能となる。
【００１１】
第４の手段は、第１，第２または第３の手段の帯電装置において、空隙制御部材を被帯電体移動方向の上流側に設けた構成としたものである。このように空隙制御部材を少なくとも被帯電体移動方向の上流側に設ければ、電磁波照射装置と電界制御電極間距離を一定に制御することができる。
【００１２】
第５の手段は、第１，第２または第３の手段の帯電装置において、空隙制御部材を被帯電体移動方向の下流側に設けた構成としたものである。このように空隙制御部材を少なくとも被帯電体移動方向の下流側に設ければ、電磁波照射装置と電界制御電極間距離を一定に制御することができる。
【００１３】
第６の手段は、第１，第２または第３の手段の帯電装置において、空隙制御部材を被帯電体移動方向の上流側と下流側の両方に設けた構成としたものである。このように空隙制御部材を被帯電体移動方向の上流側と下流側の両方に設ければ、電磁波照射装置と電界制御電極間距離を確実に一定に制御することができ、かつ電磁波照射装置からの電磁波を空隙制御部材で遮蔽することが可能となる。
【００１４】
第７の手段は、第１〜第６のいずれか１つの手段の帯電装置を複数配列し、被帯電体の広範囲を一度に帯電できるように配置した構成としたものである。すなわち帯電装置単体では被帯電体の広い範囲を一度にムラ無く帯電させることが困難であるが、第１〜第６のいずれか１つの手段の構成の帯電装置を複数配列することで、被帯電体の広範囲を帯電させることが可能となる。
【００１５】
第８の手段は、第７の手段の帯電装置において、電界制御電極と空隙制御部材とを、複数の帯電装置で共通にすると共に、前記被帯電体の長手方向に長く空隙制御部材を配置した構成としたものである（請求項２）。このように複数の帯電装置で一つの制御電極を共有することで、配線の簡略化、装置のアレー化をを行い、組み付け工程の簡素化を図ることが可能となり、さらには、空隙制御部材による電磁波遮蔽効果を向上させることが可能となる。
【００１６】
第９の手段は、第７または第８の手段の帯電装置において、複数の帯電装置のうち、被帯電体端部側の帯電装置においては、該端部側にも空隙制御部材を設けた構成としたものである（請求項１）。このように被帯電体端部側の帯電装置の端部側にも空隙制御部材を設けることにより、空隙制御部材による電磁波遮蔽効果をさらに向上させることが可能となる。
【００１７】
第１０の手段は、第１〜第９のいずれか１つの手段の帯電装置において、空隙制御部材は電磁波を透過しにくい部材で構成され、電磁波遮蔽板としての効果を持つ構成としたものである。このように空隙制御部材が電磁波遮蔽板としての効果を持つ構成とすることにより、電磁波の外部への漏洩を防止することが可能となる。
【００１８】
【発明の実施の形態】
以下、本発明の構成、動作を図面を参照して詳細に説明する。
まず本発明による非接触帯電方式の原理について述べる。電磁波が空気中に照射されると、照射された領域の空気が電離され、正負両極性のイオンが生成される。したがって被帯電体である静電潜像担持体（例えば感光体）上の空間に電磁波照射装置により電磁波を照射して空気の電離を行い、その空間に電界形成手段で電界を作用させることで、所望の極性のイオンのみを静電潜像担持体に付着させることができ、静電潜像担持体を非接触で帯電させることができる。尚、電磁波照射装置により照射される電磁波としては、紫外線、Ｘ線、軟Ｘ線、γ線等が使用できるが、電離効率や安全性の面を考慮するとＸ線か軟Ｘ線が好ましい。
【００１９】
図１は本発明による帯電装置の一実施例を示す図であり、図中の符号１は電磁波照射装置、２は静電潜像担持体である。静電潜像担持体２は例えば感光体ドラムであり、金属製の円筒からなる芯金２ｂの上に感光層２ａを形成したものである。この静電潜像担持体２の裏面側導体部である芯金２ｂには電源７によりバイアス電圧Ｖｐが印加されている。また、電磁波照射装置１と静電潜像担持体２の間で、静電潜像担持体２から高さｈｇのところには電界制御電極としてグリッド電極３が配置されている。また、電磁波照射装置１は静電潜像担持体２から高さｈのところに配置されている。そして電磁波照射装置１の少なくとも静電潜像担持体２に対向する面１ａには電源５によりバイアス電圧Ｖｉが印加され、グリッド電極３には電源６によりバイアス電圧（グリッド電圧）Ｖｇが印加されているが、ここでは、
Ｖｉ＜Ｖｇ＜Ｖｐ
なる関係を満たすように各電位を設定している。また、Ｖｉ、Ｖｇ、Ｖｐは同じ極性もしくは０Ｖである。
【００２０】
ここで、Ｖｉ、Ｖｇ、Ｖｐが同じ極性（例えば＋）で、Ｖｉ＜Ｖｇ＜Ｖｐを満たすように各電位を設定することで、例えば電磁波照射装置１とグリッド電極３間で生成されたイオンのうち負（−）のイオンは、グリッド電極３方向に力を受ける。そこでグリッド電極３を網状あるいは高密度に小孔が設けられた導電性板で構成することにより、大多数の負のイオンはグリッド電極３をすり抜けて静電潜像担持体２に付着する。また、グリッド電極３と静電潜像担持体２間で生成されたイオンも、同様に電界によって静電潜像担持体２の方向に移動し、静電潜像担持体２に付着する。これにより静電潜像担持体２の表面（感光層）２ａが負に帯電される。
【００２１】
静電潜像担持体２としては、負帯電の有機感光体（ＯＰＣ）が近年の主流である。この場合にはＶｇ、Ｖｉに負のバイアスを印加し、Ｖｐ＝０とすることで効率良く静電潜像担持体２を帯電させることができる。またこの場合はＶｉ＜Ｖｇ＜Ｖｐの関係となる。
以下に示す実施例では、静電潜像担持体２の裏面側の電極電位Ｖｐを０Ｖに設定しているが、画像形成装置の他のプロセス（露光・現像・転写等）との整合によっては必ずしも０Ｖである必要はない。例えば、Ｖｐ＝１０００Ｖとし、グリッド電極３の電位Ｖｇを５００Ｖ、電磁波照射装置１の静電潜像担持体２に対向する面１ａの電位Ｖｉを０Ｖとすることも可能である。本発明で得られた静電潜像担持体２の帯電電位は、非常に均一であり、例えば以下に示す実施例１の構成では、電位変動は±５％以下である。またオゾン発生量は、実施例１の構成で、密封容器内で装置を駆動して市販のオゾンメータで測定を行ったところ、測定不可能であった。これは用いた電磁波照射装置では、オゾン生成に必要なエネルギーの光子が全く発生しなかったためと考えられる。
【００２２】
ところで本発明の帯電方式において、各構成での様々なパラメータの影響を実験から確認したところ、電磁波照射装置１と電極間距離によって帯電電位が大きく変動する場合があることが判明した。図２に電磁波照射装置１の高さｈと静電潜像担持体２の平均帯電電位Ｖｓの関係を示す。ここで、グリッド電極３の高さをｈｇ＝３ｍｍとし、グリッド電極３にはバイアス電圧Ｖｇ＝−６００Ｖ、電磁波照射装置１にはバイアス電圧Ｖｉ＝−１０００Ｖを印加し、静電潜像担持体２の裏面側電極の電位をＶｐ＝０Ｖとした。また、電磁波照射装置１には、ターゲットにタングステンを用いた６ＫｅＶ中心の軟Ｘ線源を用いている。
【００２３】
図２より、電磁波照射装置１の高さｈが数ｍｍ変動すると帯電電位で数十Ｖばらつくことが判明した。また、電界制御電極としてのグリッド電極３は通常、網状あるいは多数の開口部を持った薄い平板であるため、電界や振動によって静電潜像担持体２からの高さｈｇが変動しやすく、よって帯電電位にばらつきが生じ易い。
【００２４】
そこで本発明では、電界制御電極としてのグリッド電極３と電磁波照射装置１との間の距離Ｈ（Ｈ＝ｈ−ｈｇ）を一定に保つことによって安定した帯電電位を得ることを目的として、電磁波照射装置１と電界制御電極（グリッド電極）３間に空隙制御部材４を設けて一体化し、電磁波照射装置と電界制御電極間距離Ｈを一定に制御する構成とした。以下、本発明の具体的な実施例について説明する。
【００２５】
（実施例１）
図３は図１に示した帯電装置の要部構成の説明図であり、空間制御部材の設置位置及び形状の一例を示す図である。図３において（ａ）は静電潜像担持体移動方向上流側から見た図、（ｂ）は静電潜像担持体軸方向（長手方向）から見た図であり、図中の符号１は電磁波照射装置、２はＯＰＣ感光体等からなる静電潜像担持体、３は電界制御電極であるグリッド電極、４ａ，４ｂは空隙制御部材である。尚、図３には図示していないが図１に示したように静電潜像担持体２の裏面側導体部である芯金２ｂにはバイアス電圧Ｖｐが印加されている。また、電磁波照射装置１としては、平均６ＫｅＶの軟Ｘ線源を用いた。
【００２６】
この電磁波照射装置１と静電潜像担持体２の間には、静電潜像担持体２から高さｈｇのところにグリッド電極３が配置されている。グリッド電極３はステンレス製の金網形状のものを採用した。網は線径０．１ｍｍでピッチ約０．８ｍｍの格子状のもので、開口率は約０．９である。このグリッド電極３にはバイアス電圧Ｖｇが印加されている。また、静電潜像担持体２は図３（ｂ）の矢印の方向に移動（回転）する。電磁波照射装置１は、電磁波照射開口部がある面１ａを静電潜像担持体２に対向するように高さｈで配置されており、この対向面１ａにはバイアス電位Ｖｉが印加されている。
本実施例ではｈ＝８ｍｍ、ｈｇ＝３ｍｍに固定し、Ｖｉ＝−１０００Ｖ、Ｖｇ＝−６００Ｖ、Ｖｐ＝０Ｖとした。また、静電潜像担持体２の移動速度ＶＬ＝４０ｍｍ／ｓｅｃである。
【００２７】
図３において、電磁波照射装置１と電界制御電極であるグリッド電極３の間には、空隙制御部材４ａ，４ｂとして高さＨ＝５ｍｍのアクリル樹脂を配置している。この空隙制御部材４ａ，４ｂは、電磁波照射装置１とグリッド電極３間の電位差を一定に保つために、絶縁体もしくは高抵抗部材である必要があるが、環境による抵抗変動を考えると絶縁体が望ましい。また、電磁波照射装置１から照射される電磁波は、波長によっては人体への悪影響が懸念されるため、可能な限り外部に漏れないようにすることが望ましい。よって、空隙制御部材４ａ，４ｂは電磁波遮蔽効果の高いものを用いた方が好ましい。また空隙制御部材４ａ，４ｂとしてはアクリルの他に塩化ビニル、テフロン、ガラス等が挙げられる。また厚さも十分に厚いほど電磁波遮蔽効果が高いため、厚さは３ｍｍ〜５ｍｍ以上が好適である。電磁波遮蔽効果は、ガラスが最も高く、次いで塩化ビニル、アクリルとなる。また、電磁波照射開口部は高温になるため、耐熱性の高いものを用いる必要がある。さらに電磁波による劣化も考慮すると、ガラスを空隙制御部材として用いるのが望ましい。ただしこれらの材料、厚さ等は、用いる電磁波の波長によって好適な材質や値が変わってくるため、この限りではない。
【００２８】
図３の構成では、空隙制御部材４ａ，４ｂにより電磁波照射装置１とグリッド電極３とが一体化され、電磁波照射装置とグリッド電極間の空隙幅Ｈが５ｍｍ一定に規定されるので、静電潜像担持体２を常に安定した電位に帯電可能となる。また、従来技術のように空隙制御部材を設けない構成（電磁波照射装置１とグリット電極３が別々に配置固定されている構成）では、電磁波照射装置１とグリッド電極３の２つの位置決めが必要なのに対して、本実施例では、電磁波照射装置１とグリッド電極３を空隙制御部材４ａ，４ｂを介して一体化することで、帯電装置の実装時における電磁波照射装置１とグリッド電極３の位置決めが一度で済むことになり、組み立て工程の簡略化につながる。
【００２９】
尚、図３（ａ）では、静電潜像担持体移動方向上流側の空隙制御部材４ａのみが見えており、下流側は隠れているが、図３（ｂ）のように、静電潜像担持体移動方向下流側にも同様の空隙制御部材４ｂを配置している。また電界制御電極の厚さが十分に厚く、振動や電界によってあまり撓まないものであれば、静電潜像担持体移動方向の上流側または下流側の一方に空隙制御部材を一つ配置すれば十分であり、装置の簡素化が図れるが、電界制御電極が金網状のような薄いグリッド電極の場合には、静電潜像担持体移動方向の上流側と下流側の両方に空隙制御電極４ａ，４ｂを配置することが望ましい。また静電潜像担持体移動方向に直交する側（静電潜像担持体の長手方向）では、電磁波の照射範囲を広くとるため、通常は空隙制御部材を配置しない方が望ましい。さらに図４に示す第２の実施例のように、静電潜像担持体の長手方向に複数の帯電装置（複数組の電磁波照射装置とグリッド電極及び空隙制御部材）を配列する場合には、隣り合った電磁波照射装置との電磁波の重ね合わせ効果が遮蔽されるため、隣り合った電磁波照射装置間には、通常は空隙制御部材を配置しない方が望ましい。
【００３０】
（実施例２）
図４は本発明の第２の実施例を示す帯電装置の構成説明図であって、帯電装置と静電潜像担持体を、静電潜像担持体移動方向上流側から見た図である。本実施例は、図３に示したような電磁波照射装置１とグリッド電極３及び空隙制御部材４ａ，４ｂから構成される帯電装置を、静電潜像担持体２の長手方向（軸方向）に複数配列し、静電潜像担持体２の長手方向の広範囲を一度にムラ無く帯電できるようにした例である。
【００３１】
図４に示す構成例では、各電磁波照射装置１とグリッド電極３の間に空隙制御部材４ａを設けて一体化し、電磁波照射装置とグリッド電極間距離を一定に制御している。また図４では、静電潜像担持体移動方向上流側の空隙制御部材４ａのみが見えており、下流側は隠れているが、図３（ｂ）と同様に、静電潜像担持体移動方向下流側にも同様の空隙制御部材４ｂを配置することが好ましい。また静電潜像担持体長手方向では、隣り合った電磁波照射装置間の電磁波の重ね合わせ効果を得るため、隣り合った電磁波照射装置間には、空隙制御部材を配置していないが、静電潜像担持体２の端部側では重ね合わせ効果が必要ないために、静電潜像担持体長手方向の両端部側には空隙制御部材４ｃ，４ｄを配置することが好ましい。さらに静電潜像担持体長手方向の両端部側に空隙制御部材４ｃ，４ｄを配置することによって、両端部から外部に漏洩する電磁波を遮蔽することが可能となり、安全性が向上する。
【００３２】
図４の構成例のように複数の電磁波照射装置１やグリッド電極３を配置する場合には、各電磁波照射装置１とグリッド電極３の間に空隙制御部材４ａを設けて一体化し、電磁波照射装置とグリッド電極間距離を一定に制御することが特に有効である。すなわち、空隙制御部材を設けない構成（複数の電磁波照射装置１とグリット電極３が別々に配置固定されている構成）では、複数の電磁波照射装置１とグリッド電極３の位置決めが必要なのに対して、本実施例では、各電磁波照射装置１とグリッド電極３とを空隙制御部材を介して一体化しているので、帯電装置の実装時における各電磁波照射装置１とグリッド電極３の位置決めが一度で済むことになり、組み立て工程の簡略化につながる。
【００３３】
（実施例３）
図５は本発明の第３の実施例を示す帯電装置の構成説明図であって、帯電装置と静電潜像担持体を、静電潜像担持体移動方向上流側から見た図である。本実施例は、図４と同様に、電磁波照射装置１と電界制御電極（グリッド電極）３からなる帯電装置を静電潜像担持体２の長手方向（軸方向）に複数配列し、静電潜像担持体２の長手方向の広範囲を一度にムラ無く帯電できるようにした例であるが、図５に示す構成例では、電界制御電極３を複数の帯電装置で共通の電極としている。より具体的には、電界制御電極３を静電潜像担持体２の長手方向（軸方向）に長く形成し、３つの電磁波照射装置１に対して、１つの電界制御電極３を配置している。また、電磁波照射装置と電界制御電極間に設けられる空隙制御部材４ｅは電界制御電極３の長さに合わせて電極長手方向に一様に取り付けられている。尚、図５では、静電潜像担持体移動方向上流側の空隙制御部材４ｅのみが見えており、下流側は隠れているが、通常、静電潜像担持体移動方向下流側にも同様の構成の空隙制御部材が配置される。
【００３４】
図５に示すように、複数の電磁波照射装置１に対して電界制御電極３と空隙制御部材４ｅを共通に設け、静電潜像担持体２の長手方向に長く空隙制御部材４ｅを配置することにより、電磁波遮蔽効果が高まり、電磁波の外部への漏洩防止効果が向上する。また、複数の帯電装置（電磁波照射装置）で一つの電界制御電極３を共有することで、電界制御電極３への配線が減り、コスト削減や工程の削減になる。また電界制御電極３と空隙制御部材４ｅを共通に設けて装置のアレー化を行うので、組み付け工程の簡素化にもなる。
【００３５】
（実施例４）
図６は本発明の第４の実施例を示す帯電装置の構成説明図であって、帯電装置と静電潜像担持体を、静電潜像担持体移動方向上流側から見た図である。本実施例は、図４、図５と同様に、電磁波照射装置１と電界制御電極（グリッド電極）３からなる帯電装置を静電潜像担持体２の長手方向（軸方向）に複数配列し、静電潜像担持体２の長手方向の広範囲を一度にムラ無く帯電できるようにした例であるが、図６に示す構成例では、電界制御電極３を全ての帯電装置で共通の電極としている。より具体的には、電界制御電極３を静電潜像担持体２の長手方向（軸方向）に長く一体に形成し、６つの電磁波照射装置１に対して、１つの電界制御電極３を一体に配置している。また、電磁波照射装置と電界制御電極間に設けられる空隙制御部材４ｆも電界制御電極３に合わせて電極長手方向に一様に取り付けられている。尚、図６では、静電潜像担持体移動方向上流側の空隙制御部材４ｆのみが見えており、下流側は隠れているが、通常、静電潜像担持体移動方向下流側にも同様の構成の空隙制御部材が配置される。
【００３６】
図６に示すように、全ての電磁波照射装置１に対して電界制御電極３と空隙制御部材４ｆを共通に設け、静電潜像担持体２の長手方向に長く空隙制御部材４ｆを配置することにより、空隙制御部材間の隙間から漏洩する電磁波が大幅に減少するため、電磁波遮蔽効果がより一層高まり、電磁波の外部への漏洩防止効果がより一層向上する。また、全ての電磁波照射装置１で一つの電界制御電極３を共有することで、電界制御電極３への配線が１つで済み、コスト削減や工程の削減になる。また全ての電磁波照射装置１に対して電界制御電極３と空隙制御部材４ｅを共通に設けて帯電装置アレーとしているので、静電潜像担持体２に対する帯電装置アレーの位置決めが一度で済み、組み付け工程をより一層簡素化できる。
【００３７】
【発明の効果】
以上説明したように、第１の手段の帯電装置においては、電磁波照射装置と被帯電体（例えば画像形成装置の静電潜像担持体）の間に電界制御電極を配設して電界を制御すると共に、前記電磁波照射装置と電界制御電極間に空隙制御部材を設けて一体化し、電磁波照射装置と電界制御電極間距離を一定に制御する構成としたことにより、電磁波照射装置と電界制御電極間距離を一定に制御することができ、電磁波照射装置と電極間の電界強度を常に一定に保つことができるので、振動や経時においても安定した帯電電位を確保することができる。また電磁波照射装置と電界制御電極を空隙制御部材を設けて一体化することで、組み立て時の位置決め制御を簡略化することができる。
【００３８】
第２の手段の帯電装置においては、第１の手段の構成及び効果に加えて、空隙制御部材を絶縁体で構成したことにより、電磁波照射装置と電界制御電極間での電位差を一定に保ち、短絡を防止することができる。
【００３９】
第３の手段の帯電装置においては、第１または第２の手段の構成及び効果に加えて、電界制御電極を、多数の開口部を有するグリッド形状としたことにより、電磁波により生成されたイオンを確実に被帯電体に移動して付着させることができ、該被帯電体を帯電させることができる。
【００４０】
第４の手段の帯電装置においては、第１，第２または第３の構成及び効果に加えて、空隙制御部材を被帯電体移動方向の上流側に設けた構成としたことにより、簡素な構成で電磁波照射装置と電界制御電極間距離を一定に制御することができる。
【００４１】
第５の手段の帯電装置においては、第１，第２または第３の手段の構成及び効果に加えて、空隙制御部材を被帯電体移動方向の下流側に設けた構成としたことにより、簡素な構成で電磁波照射装置と電界制御電極間距離を一定に制御することができる。
【００４２】
第６の手段の帯電装置においては、第１，第２または第３の手段の構成及び効果に加えて、空隙制御部材を被帯電体移動方向の上流側と下流側の両方に設けた構成としたことにより、電磁波照射装置と電界制御電極間距離を確実に一定に制御することができ、かつ電磁波照射装置からの電磁波を空隙制御部材で遮蔽することが可能となる。
【００４３】
第７の手段の帯電装置においては、第１〜第６のいずれか１つの手段の構成の帯電装置を複数配列し、被帯電体の広範囲を一度に帯電できるように配置した構成としたものであり、帯電装置単体では被帯電体の広い範囲を一度にムラ無く帯電させることが困難であったが、第１〜第６のいずれか１つの手段の構成の帯電装置を複数配列することで、被帯電体の広範囲を一度にムラ無く帯電させることができる。
【００４４】
第８の手段の帯電装置においては、第７の手段の構成及び効果に加えて、電界制御電極と空隙制御部材とを、複数の帯電装置で共通にすると共に、前記被帯電体の長手方向に長く空隙制御部材を配置した構成としたものであり、このように複数の帯電装置で一つの制御電極を共有することで、配線の簡略化、装置のアレー化をを行い、組み付け工程の簡素化を図ることができ、さらには、空隙制御部材による電磁波遮蔽効果を向上させることができ、安全性を確保することができる。
【００４５】
第９の手段の帯電装置においては、第７または第８の手段の構成及び効果に加えて、複数の帯電装置のうち、被帯電体端部側の帯電装置においては、該端部側にも空隙制御部材を設けた構成としたものであり、このように被帯電体端部側の帯電装置の端部側にも空隙制御部材を設けることにより、空隙制御部材による電磁波遮蔽効果をさらに向上させることができ、安全性を確保することができる。
【００４６】
第１０の手段の帯電装置においては、第１〜第９のいずれか１つの手段の構成及び効果に加えて、空隙制御部材は電磁波を透過しにくい部材で構成され、電磁波遮蔽板としての効果を持つ構成としたものであり、このように空隙制御部材が電磁波遮蔽板としての効果を持つ構成とすることにより、電磁波の外部への漏洩を防止することができ、装置の安全性をさらに向上させることができる。
【図面の簡単な説明】
【図１】本発明の一実施例を示す帯電装置の構成説明図である。
【図２】図１に示す電磁波照射装置の高さｈと静電潜像担持体の帯電電位Ｖｓの関係を示す図である。
【図３】図１に示した帯電装置の要部構成の説明図であり、空間制御部材の設置位置及び形状の一実施例を示す図である。
【図４】本発明の第２の実施例を示す帯電装置の構成説明図である。
【図５】本発明の第３の実施例を示す帯電装置の構成説明図である。
【図６】本発明の第４の実施例を示す帯電装置の構成説明図である。
【符号の説明】
１：電磁波照射装置
２：静電潜像担持体（被帯電体）
２ａ：感光層
２ｂ：芯金
３：グリッド電極（電界制御電極）
４，４ａ，４ｂ，４ｃ，４ｄ，４ｅ，４ｆ：空隙制御部材
５，６，７：バイアス印加用電源[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device applied to a charging unit of an image forming apparatus using electrophotographic technology such as a copying machine, a facsimile machine, a printer, and the like, and in particular, a charged body such as an electrostatic latent image carrier is uniformly contactless. The present invention relates to a charging device for charging a battery.
[0002]
[Prior art]
In an image forming process using a copying machine, a facsimile, a printer, or the like using electrophotographic technology, there is a process for charging a photosensitive member that is an electrostatic latent image carrier. This charging process has been conventionally performed by a corona charger that is non-contact and excellent in charging stability. However, since this system generates a lot of ozone, a contact charging system has recently been studied. A contact charging method (a roller charging method using a conductive roller, in which an AC voltage is superimposed on a DC voltage and applied to the conductive roller) as disclosed in JP-A-63-149669, , A brush charging device as disclosed in JP-A-6-175469 (a brush charging method using a conductive brush, and an intermediate conductive member having a low resistance is provided between the conductive brush and the metal core, (Eliminating the environmental dependency of charging and charging the object to be charged uniformly) has been put into practical use.
[0003]
However, in the contact charging method, since the charging member is in contact with an electrostatic latent image carrier such as a photoconductor, the charging member is easily contaminated with toner, and as a result, charging performance such as uneven charging occurs. .
From the above, it can be said that the ozone-less non-contact charging method is ideal as the charging means.
[0004]
Therefore, the present inventors previously provided an electromagnetic wave irradiation device and an electric field forming unit, and by applying an electromagnetic wave to the space on the electrostatic latent image carrier by the electromagnetic wave irradiation device and forming an electric field by the electric field forming unit, A charging device for charging the electrostatic latent image carrier to a desired potential has been proposed (Japanese Patent Laid-Open Nos. 9-218561 and 9-325579).
In this charging device, a grid electrode is provided between the electromagnetic wave irradiation device and the electrostatic latent image carrier to control the electric field, and by appropriately applying the electromagnetic wave and the electric field, ions generated by the electromagnetic wave are efficiently electrostatically charged. The electrostatic latent image bearing member can be non-contact charged by being attached to the latent image bearing member, the charging reliability can be improved, and uniform charging with little charging unevenness is possible.
[0005]
[Problems to be solved by the invention]
However, the charging device of the prior application has a problem that the charging potential of the electrostatic latent image carrier fluctuates when the distance between the electromagnetic wave irradiation device and the grid electrode for electric field control changes with vibration or over time. In particular, since the grid electrode is usually a thin flat plate or net-like electrode having a large number of openings, the distance from the electromagnetic wave irradiation device or the electrostatic latent image carrier is likely to fluctuate due to an electric field or vibration, and the charged potential varies. easy. In addition, there is a problem that it takes time to control positioning when assembling the electromagnetic wave irradiation device and the grid electrode.
[0006]
The present invention has been made in view of the above circumstances, and includes an electromagnetic wave irradiation device and an electric field forming unit. The electromagnetic wave irradiation device irradiates an electromagnetic wave into a space on a charged body and forms an electric field with the electric field forming unit. In an ozone-less non-contact charging system that charges an object to be charged to a desired potential, a stable charging potential can be obtained by keeping the distance between the electric field control electrode and the electromagnetic wave irradiation device constant. The challenge
(Purpose). less than The present invention Enumerates the issues to be solved.
[0007]
(1): By controlling the distance between the electromagnetic wave irradiation device and the electric field control electrode to be constant, the electric field intensity between the electromagnetic wave irradiation device and the electrode can be kept constant at all times, and it is necessary to ensure a stable charging potential even during vibration and aging And It is another object of the present invention to simplify positioning control during assembly by integrating the electromagnetic wave irradiation device and the electric field control electrode.
(2): (1) In addition to the above problem, it is an object to keep the potential difference between the electromagnetic wave irradiation device and the electric field control electrode constant and prevent a short circuit.
(3): (1) or (2) In addition to the above problem, it is an object to reliably move ions generated by electromagnetic waves to an object to be charged.
(4): (1), (2) or (3) In addition to the above problem, it is an object of the present invention to simplify the apparatus by defining a minimum necessary installation position of means for controlling the distance between the electromagnetic wave irradiation apparatus and the electric field control electrode to be constant.
(5): (1), (2) or (3) In addition to the above problem, it is an object to define the installation position of means for reliably controlling the distance between the electromagnetic wave irradiation device and the electric field control electrode and to shield the electromagnetic wave.
(6): (1) to (5) In addition to any of the above problems, an object is to provide a structure capable of charging a wide range of an object to be charged at a time.
(7) :( 6) In addition to the above problems, it is an object to simplify the wiring process and array the apparatus to simplify the assembly process, and to improve the electromagnetic wave shielding effect and ensure safety.
(8): (6) or (7) In addition to the above problems, it is an object to further improve the electromagnetic wave shielding effect and ensure safety.
(9): (1) to (8) In addition to any of the above problems, it is an object to reliably prevent leakage of electromagnetic waves to the outside and improve the safety of the apparatus.
[0008]
[Means for Solving the Problems]
To solve the above problems First means Comprises an electromagnetic wave irradiating device and an electric field forming means. The electromagnetic wave irradiating device irradiates the space on the object to be charged with electromagnetic waves and forms an electric field with the electric field forming means, thereby causing the object to be charged to have a desired potential Vs. In the charging device to be charged, the electric field control electrode is disposed between the electromagnetic wave irradiation device and the object to be charged, and the electric field is controlled, and a gap control member is provided between the electromagnetic wave irradiation device and the electric field control electrode. The distance between the electromagnetic wave irradiation device and the electric field control electrode is controlled to be constant. As a result, the distance between the electromagnetic wave irradiation device and the electric field control electrode can be controlled to be constant, and the electric field strength between the electromagnetic wave irradiation device and the electrode can always be kept constant. Further, the electromagnetic wave irradiation device and the electric field control electrode can be integrated by providing a gap control member, thereby simplifying positioning control during assembly.
[0009]
The second means is the first means In the charging device, the air gap control member is made of an insulator. If the gap control member is made of an insulator as described above, the potential difference between the electromagnetic wave irradiation device and the electric field control electrode can be kept constant, and a short circuit can be prevented.
[0010]
The third means is the first or second means In this charging device, the electric field control electrode has a grid shape having a large number of openings. If the electric field control electrode is formed in a grid shape having a large number of openings as described above, ions generated by electromagnetic waves can be reliably moved to the charged body.
[0011]
The fourth means is the first, second or third means. In this charging apparatus, the gap control member is provided on the upstream side in the moving direction of the charged object. As described above, when the air gap control member is provided at least upstream in the moving direction of the charged object, the distance between the electromagnetic wave irradiation device and the electric field control electrode can be controlled to be constant.
[0012]
The fifth means is the first, second or third means In this charging device, the gap control member is provided on the downstream side in the moving direction of the charged object. As described above, when the gap control member is provided at least on the downstream side in the moving direction of the member to be charged, the distance between the electromagnetic wave irradiation device and the electric field control electrode can be controlled to be constant.
[0013]
The sixth means is the first, second or third means. In this charging apparatus, the air gap control member is provided on both the upstream side and the downstream side in the charged object moving direction. If the air gap control member is provided on both the upstream side and the downstream side in the moving direction of the charged body in this way, the distance between the electromagnetic wave irradiation device and the electric field control electrode can be controlled reliably and from the electromagnetic wave irradiation device. The electromagnetic wave can be shielded by the air gap control member.
[0014]
The seventh means is any one of the first to sixth means A plurality of charging devices are arranged so that a wide range of the object to be charged can be charged at once. In other words, it is difficult to charge a wide range of charged objects at once without unevenness with a single charging device, Any one of the first to sixth means By arranging a plurality of charging devices having the above configuration, it is possible to charge a wide range of the object to be charged.
[0015]
The eighth means is the seventh means Electric field control electrode And gap control member Common to multiple charging devices In And The object to be charged The gap control member is arranged long in the longitudinal direction of (Claim 2) . In this way, by sharing one control electrode among a plurality of charging devices, it is possible to simplify wiring and array the device, simplify the assembly process, and further, by using a gap control member It is possible to improve the electromagnetic wave shielding effect.
[0016]
The ninth means is the seventh or eighth means Among the plurality of charging devices, the charging device on the charged object end side has a configuration in which a gap control member is also provided on the end side. (Claim 1) . Thus, by providing the gap control member also on the end side of the charging device on the charged body end side, the electromagnetic wave shielding effect by the gap control member can be further improved.
[0017]
The tenth means is any one of the first to ninth means In this charging device, the air gap control member is made of a material that hardly transmits electromagnetic waves, and has an effect as an electromagnetic wave shielding plate. Thus, by setting the air gap control member as an electromagnetic wave shielding plate, leakage of electromagnetic waves to the outside can be prevented.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the drawings.
First, the principle of the non-contact charging method according to the present invention will be described. When the electromagnetic wave is irradiated into the air, the air in the irradiated region is ionized, and positive and negative ions are generated. Therefore, by applying electromagnetic waves to the space on the electrostatic latent image carrier (e.g., photoconductor), which is the object to be charged, by electromagnetic wave irradiation device to ionize the air, and by applying an electric field to the space by the electric field forming means, Only ions having a desired polarity can be attached to the electrostatic latent image carrier, and the electrostatic latent image carrier can be charged in a non-contact manner. In addition, as electromagnetic waves irradiated by the electromagnetic wave irradiation device, ultraviolet rays, X-rays, soft X-rays, γ-rays and the like can be used, but X-rays or soft X-rays are preferable in view of ionization efficiency and safety.
[0019]
FIG. 1 is a view showing an embodiment of a charging device according to the present invention. In FIG. 1, reference numeral 1 denotes an electromagnetic wave irradiation device, and 2 denotes an electrostatic latent image carrier. The electrostatic latent image carrier 2 is, for example, a photosensitive drum, and has a photosensitive layer 2a formed on a cored bar 2b made of a metal cylinder. A bias voltage Vp is applied by a power source 7 to a cored bar 2b which is a back side conductor portion of the electrostatic latent image carrier 2. In addition, a grid electrode 3 is disposed as an electric field control electrode between the electromagnetic wave irradiation device 1 and the electrostatic latent image carrier 2 at a height hg from the electrostatic latent image carrier 2. The electromagnetic wave irradiation device 1 is disposed at a height h from the electrostatic latent image carrier 2. A bias voltage Vi is applied by a power source 5 to at least the surface 1a of the electromagnetic wave irradiation device 1 facing the electrostatic latent image carrier 2, and a bias voltage (grid voltage) Vg is applied to the grid electrode 3 by a power source 6. But here
Vi <Vg <Vp
Each potential is set so as to satisfy the following relationship. Vi, Vg, and Vp have the same polarity or 0V.
[0020]
Here, by setting each potential so that Vi, Vg, and Vp have the same polarity (for example, +) and satisfy Vi <Vg <Vp, for example, ions generated between the electromagnetic wave irradiation device 1 and the grid electrode 3 Among these, negative (−) ions receive a force in the direction of the grid electrode 3. Therefore, the grid electrode 3 is formed of a conductive plate having a net-like or high-density small hole so that the majority of negative ions pass through the grid electrode 3 and adhere to the electrostatic latent image carrier 2. Similarly, ions generated between the grid electrode 3 and the electrostatic latent image carrier 2 are also moved in the direction of the electrostatic latent image carrier 2 by the electric field, and adhere to the electrostatic latent image carrier 2. As a result, the surface (photosensitive layer) 2a of the electrostatic latent image carrier 2 is negatively charged.
[0021]
As the electrostatic latent image carrier 2, a negatively charged organic photoconductor (OPC) has been the mainstream in recent years. In this case, the electrostatic latent image carrier 2 can be efficiently charged by applying a negative bias to Vg and Vi and setting Vp = 0. In this case, Vi <Vg <Vp.
In the embodiment described below, the electrode potential Vp on the back surface side of the electrostatic latent image carrier 2 is set to 0 V. However, depending on the alignment with other processes (exposure, development, transfer, etc.) of the image forming apparatus. It is not necessarily 0V. For example, it is possible to set Vp = 1000V, the potential Vg of the grid electrode 3 to 500V, and the potential Vi of the surface 1a facing the electrostatic latent image carrier 2 of the electromagnetic wave irradiation device 1 to 0V. The charged potential of the electrostatic latent image carrier 2 obtained in the present invention is very uniform. For example, in the configuration of Example 1 shown below, the potential fluctuation is ± 5% or less. The amount of ozone generated was not measurable when the apparatus was driven in a sealed container with the configuration of Example 1 and measured with a commercially available ozone meter. This is probably because the electromagnetic wave irradiation apparatus used did not generate photons of energy necessary for ozone generation.
[0022]
By the way, in the charging method of the present invention, when the influence of various parameters in each configuration was confirmed from experiments, it was found that the charging potential may vary greatly depending on the distance between the electromagnetic wave irradiation device 1 and the electrode. FIG. 2 shows the relationship between the height h of the electromagnetic wave irradiation device 1 and the average charging potential Vs of the electrostatic latent image carrier 2. Here, the height of the grid electrode 3 is set to hg = 3 mm, the bias voltage Vg = −600 V is applied to the grid electrode 3, the bias voltage Vi = −1000 V is applied to the electromagnetic wave irradiation device 1, and the electrostatic latent image carrier 2 is applied. The potential of the back side electrode was set to Vp = 0V. The electromagnetic wave irradiation device 1 uses a 6 KeV center soft X-ray source using tungsten as a target.
[0023]
From FIG. 2, it was found that when the height h of the electromagnetic wave irradiation device 1 fluctuates by several mm, the charged potential varies by several tens of volts. Further, since the grid electrode 3 as an electric field control electrode is usually a net or a thin flat plate having a large number of openings, the height hg from the electrostatic latent image carrier 2 is likely to fluctuate due to an electric field or vibration. The charged potential is likely to vary.
[0024]
Therefore, in the present invention, for the purpose of obtaining a stable charging potential by keeping the distance H (H = h−hg) between the grid electrode 3 as the electric field control electrode and the electromagnetic wave irradiation device 1 constant, electromagnetic wave irradiation is performed. A gap control member 4 is provided and integrated between the device 1 and the electric field control electrode (grid electrode) 3 so that the distance H between the electromagnetic wave irradiation device and the electric field control electrode is controlled to be constant. Hereinafter, specific examples of the present invention will be described.
[0025]
Example 1
FIG. 3 is an explanatory diagram of a main part configuration of the charging device shown in FIG. 3A is a view as seen from the upstream side in the moving direction of the electrostatic latent image carrier, and FIG. 3B is a view as seen from the axial direction (longitudinal direction) of the electrostatic latent image carrier. Is an electromagnetic wave irradiation device, 2 is an electrostatic latent image carrier made of an OPC photoreceptor, 3 is a grid electrode as an electric field control electrode, and 4a and 4b are air gap control members. Although not shown in FIG. 3, a bias voltage Vp is applied to the cored bar 2b, which is a conductor portion on the back surface side of the electrostatic latent image carrier 2, as shown in FIG. As the electromagnetic wave irradiation device 1, a soft X-ray source having an average of 6 KeV was used.
[0026]
Between the electromagnetic wave irradiation device 1 and the electrostatic latent image carrier 2, a grid electrode 3 is disposed at a height hg from the electrostatic latent image carrier 2. The grid electrode 3 was a stainless steel wire mesh. The net has a lattice shape with a wire diameter of 0.1 mm and a pitch of about 0.8 mm, and the aperture ratio is about 0.9. A bias voltage Vg is applied to the grid electrode 3. Further, the electrostatic latent image carrier 2 moves (rotates) in the direction of the arrow in FIG. The electromagnetic wave irradiation device 1 is disposed at a height h so that the surface 1a having the electromagnetic wave irradiation opening is opposed to the electrostatic latent image carrier 2, and a bias potential Vi is applied to the facing surface 1a. .
In this embodiment, h = 8 mm and hg = 3 mm are fixed, and Vi = −1000 V, Vg = −600 V, and Vp = 0 V. Further, the moving speed VL of the electrostatic latent image carrier 2 is 40 mm / sec.
[0027]
In FIG. 3, an acrylic resin having a height H = 5 mm is disposed as the gap control members 4a and 4b between the electromagnetic wave irradiation device 1 and the grid electrode 3 which is an electric field control electrode. The gap control members 4a and 4b need to be insulators or high-resistance members in order to keep the potential difference between the electromagnetic wave irradiation device 1 and the grid electrode 3 constant. desirable. Moreover, since the electromagnetic wave irradiated from the electromagnetic wave irradiation apparatus 1 may be anxious about the bad influence on a human body depending on a wavelength, it is desirable not to leak outside as much as possible. Therefore, it is preferable to use the air gap control members 4a and 4b having a high electromagnetic shielding effect. In addition to acrylic, examples of the air gap control members 4a and 4b include vinyl chloride, Teflon, and glass. Moreover, since the electromagnetic wave shielding effect is higher as the thickness is sufficiently thick, the thickness is preferably 3 mm to 5 mm or more. The electromagnetic wave shielding effect is the highest in glass, followed by vinyl chloride and acrylic. Moreover, since the electromagnetic wave irradiation opening becomes high temperature, it is necessary to use one having high heat resistance. Furthermore, considering deterioration due to electromagnetic waves, it is desirable to use glass as a gap control member. However, these materials, thicknesses, and the like are not limited to this, because suitable materials and values vary depending on the wavelength of the electromagnetic wave used.
[0028]
In the configuration of FIG. 3, the electromagnetic wave irradiation device 1 and the grid electrode 3 are integrated by the air gap control members 4a and 4b, and the air gap width H between the electromagnetic wave irradiation device and the grid electrode is regulated to be 5 mm. The image carrier 2 can always be charged to a stable potential. Further, in the configuration in which the gap control member is not provided as in the prior art (the configuration in which the electromagnetic wave irradiation device 1 and the grit electrode 3 are separately arranged and fixed), two positioning of the electromagnetic wave irradiation device 1 and the grid electrode 3 is necessary. On the other hand, in this embodiment, the electromagnetic wave irradiation device 1 and the grid electrode 3 are integrated via the gap control members 4a and 4b, so that the electromagnetic wave irradiation device 1 and the grid electrode 3 are positioned once when the charging device is mounted. This leads to simplification of the assembly process.
[0029]
In FIG. 3A, only the gap control member 4a on the upstream side in the moving direction of the electrostatic latent image carrier is visible and the downstream side is hidden, but as shown in FIG. A similar air gap control member 4b is also arranged on the downstream side in the moving direction of the image carrier. If the electric field control electrode is sufficiently thick and does not bend very much due to vibration or electric field, one gap control member should be arranged on either the upstream side or the downstream side in the direction of movement of the electrostatic latent image carrier. However, if the electric field control electrode is a thin grid electrode such as a wire mesh, the gap control electrode is provided on both the upstream side and the downstream side in the moving direction of the electrostatic latent image carrier. It is desirable to arrange 4a and 4b. On the side orthogonal to the moving direction of the electrostatic latent image carrier (longitudinal direction of the electrostatic latent image carrier), it is usually desirable not to arrange the air gap control member in order to widen the irradiation range of the electromagnetic wave. Further, as in the second embodiment shown in FIG. 4, when a plurality of charging devices (a plurality of sets of electromagnetic wave irradiation devices and grid electrodes and gap control members) are arranged in the longitudinal direction of the electrostatic latent image carrier, Since the effect of superimposing electromagnetic waves with adjacent electromagnetic wave irradiation devices is shielded, it is usually desirable not to arrange a gap control member between adjacent electromagnetic wave irradiation devices.
[0030]
(Example 2)
FIG. 4 is a diagram illustrating the configuration of a charging device according to a second embodiment of the present invention, and is a view of the charging device and the electrostatic latent image carrier viewed from the upstream side in the moving direction of the electrostatic latent image carrier. . In the present embodiment, the charging device including the electromagnetic wave irradiation device 1, the grid electrode 3, and the gap control members 4 a and 4 b as shown in FIG. 3 is arranged in the longitudinal direction (axial direction) of the electrostatic latent image carrier 2. In this example, a plurality of arrays are arranged so that a wide area in the longitudinal direction of the electrostatic latent image carrier 2 can be charged at once without unevenness.
[0031]
In the configuration example shown in FIG. 4, a gap control member 4a is provided and integrated between each electromagnetic wave irradiation device 1 and the grid electrode 3, and the distance between the electromagnetic wave irradiation device and the grid electrode is controlled to be constant. In FIG. 4, only the air gap control member 4a on the upstream side in the moving direction of the electrostatic latent image carrier is visible and the downstream side is hidden, but as in FIG. 3B, the electrostatic latent image carrier is moved. It is preferable to arrange a similar gap control member 4b on the downstream side in the direction. Also, in the longitudinal direction of the electrostatic latent image carrier, in order to obtain the effect of superimposing electromagnetic waves between adjacent electromagnetic wave irradiation devices, no gap control member is disposed between the adjacent electromagnetic wave irradiation devices. Since no overlapping effect is required on the end side of the latent image carrier 2, it is preferable to dispose the gap control members 4c and 4d on both end sides in the longitudinal direction of the electrostatic latent image carrier. Furthermore, by disposing the gap control members 4c and 4d on both ends in the longitudinal direction of the electrostatic latent image carrier, it is possible to shield electromagnetic waves leaking to the outside from both ends, thereby improving safety.
[0032]
When a plurality of electromagnetic wave irradiation devices 1 and grid electrodes 3 are arranged as in the configuration example of FIG. 4, a gap control member 4 a is provided and integrated between each electromagnetic wave irradiation device 1 and the grid electrode 3. It is particularly effective to control the distance between the grid electrodes to be constant. That is, in the configuration in which the gap control member is not provided (the configuration in which the plurality of electromagnetic wave irradiation devices 1 and the grit electrodes 3 are separately arranged and fixed), the positioning of the plurality of electromagnetic wave irradiation devices 1 and the grid electrodes 3 is required. In this embodiment, since each electromagnetic wave irradiation device 1 and the grid electrode 3 are integrated via a gap control member, the positioning of each electromagnetic wave irradiation device 1 and the grid electrode 3 at the time of mounting the charging device can be performed only once. This leads to simplification of the assembly process.
[0033]
Example 3
FIG. 5 is a diagram illustrating the configuration of a charging device according to a third embodiment of the present invention, in which the charging device and the electrostatic latent image carrier are viewed from the upstream side in the moving direction of the electrostatic latent image carrier. . In the present embodiment, similarly to FIG. 4, a plurality of charging devices each including an electromagnetic wave irradiation device 1 and an electric field control electrode (grid electrode) 3 are arranged in the longitudinal direction (axial direction) of the electrostatic latent image carrier 2, In this example, a wide area in the longitudinal direction of the latent image carrier 2 can be charged at once without unevenness. In the configuration example shown in FIG. 5, the electric field control electrode 3 is used as a common electrode in a plurality of charging devices. More specifically, the electric field control electrode 3 is formed long in the longitudinal direction (axial direction) of the electrostatic latent image carrier 2, and one electric field control electrode 3 is arranged for the three electromagnetic wave irradiation devices 1. Yes. Further, the gap control member 4e provided between the electromagnetic wave irradiation device and the electric field control electrode is uniformly attached in the longitudinal direction of the electrode according to the length of the electric field control electrode 3. In FIG. 5, only the air gap control member 4e on the upstream side in the electrostatic latent image carrier moving direction is visible and the downstream side is hidden. The air gap control member having the structure is arranged.
[0034]
As shown in FIG. 5, the electric field control electrode 3 and the gap control member 4e are provided in common for the plurality of electromagnetic wave irradiation devices 1, and the gap control member 4e is disposed long in the longitudinal direction of the electrostatic latent image carrier 2. Thus, the electromagnetic wave shielding effect is enhanced, and the effect of preventing leakage of electromagnetic waves to the outside is improved. Further, by sharing one electric field control electrode 3 among a plurality of charging devices (electromagnetic wave irradiation devices), the wiring to the electric field control electrode 3 is reduced, thereby reducing costs and processes. In addition, since the electric field control electrode 3 and the gap control member 4e are provided in common and the apparatus is arrayed, the assembly process can be simplified.
[0035]
Example 4
FIG. 6 is a diagram illustrating the configuration of a charging device according to a fourth embodiment of the present invention, in which the charging device and the electrostatic latent image carrier are viewed from the upstream side in the moving direction of the electrostatic latent image carrier. . In this embodiment, similarly to FIGS. 4 and 5, a plurality of charging devices each including an electromagnetic wave irradiation device 1 and an electric field control electrode (grid electrode) 3 are arranged in the longitudinal direction (axial direction) of the electrostatic latent image carrier 2. In the example shown in FIG. 6, the electric field control electrode 3 is used as a common electrode in all charging devices. In the configuration example shown in FIG. Yes. More specifically, the electric field control electrode 3 is integrally formed long in the longitudinal direction (axial direction) of the electrostatic latent image carrier 2, and one electric field control electrode 3 is integrated with the six electromagnetic wave irradiation devices 1. Is arranged. A gap control member 4 f provided between the electromagnetic wave irradiation device and the electric field control electrode is also uniformly attached in the electrode longitudinal direction in accordance with the electric field control electrode 3. In FIG. 6, only the gap control member 4f on the upstream side in the moving direction of the electrostatic latent image carrier is visible and the downstream side is hidden. The air gap control member having the structure is arranged.
[0036]
As shown in FIG. 6, the electric field control electrode 3 and the gap control member 4f are provided in common for all the electromagnetic wave irradiation devices 1, and the gap control member 4f is arranged long in the longitudinal direction of the electrostatic latent image carrier 2. As a result, electromagnetic waves leaking from the gaps between the gap control members are significantly reduced, so that the electromagnetic wave shielding effect is further enhanced, and the electromagnetic wave leakage prevention effect is further improved. In addition, by sharing one electric field control electrode 3 in all the electromagnetic wave irradiation apparatuses 1, only one wiring to the electric field control electrode 3 is required, thereby reducing costs and processes. In addition, since the electric field control electrode 3 and the gap control member 4e are provided in common for all the electromagnetic wave irradiation devices 1 to form a charging device array, the positioning of the charging device array with respect to the electrostatic latent image carrier 2 can be performed only once. The process can be further simplified.
[0037]
【The invention's effect】
As explained above, First means In this charging device, an electric field control electrode is disposed between the electromagnetic wave irradiation device and a member to be charged (for example, an electrostatic latent image carrier of the image forming apparatus) to control the electric field, and the electromagnetic wave irradiation device and the electric field control. By providing a gap control member between the electrodes and integrating them, the distance between the electromagnetic wave irradiation device and the electric field control electrode is controlled to be constant, so that the distance between the electromagnetic wave irradiation device and the electric field control electrode can be controlled to be constant, Since the electric field strength between the electromagnetic wave irradiation device and the electrode can always be kept constant, a stable charging potential can be ensured even during vibration and aging. Moreover, positioning control at the time of an assembly can be simplified by providing an electromagnetic wave irradiation apparatus and an electric field control electrode by providing a gap control member.
[0038]
Second means In the charging device of First means In addition to the configuration and the effect described above, the gap control member is made of an insulator, so that the potential difference between the electromagnetic wave irradiation device and the electric field control electrode can be kept constant and a short circuit can be prevented.
[0039]
Third means In the charging device of First or second means In addition to the configuration and effects of the above, by forming the electric field control electrode in a grid shape having a large number of openings, the ions generated by the electromagnetic waves can be reliably moved and adhered to the object to be charged. The charged body can be charged.
[0040]
Fourth means In the charging device of 1st, 2nd or 3rd In addition to the configuration and effect of the above, the gap control member is provided on the upstream side in the charged body moving direction, so that the distance between the electromagnetic wave irradiation device and the electric field control electrode can be controlled to be constant with a simple configuration. .
[0041]
5th means In the charging device of First, second or third means In addition to the configuration and the effect of the above, the gap control member is provided on the downstream side in the moving direction of the charged body, so that the distance between the electromagnetic wave irradiation device and the electric field control electrode can be controlled to be constant with a simple configuration. .
[0042]
Sixth means In the charging device of First, second or third means In addition to the configuration and effect of the above, the gap control member is provided on both the upstream side and the downstream side in the moving direction of the charged body, thereby reliably controlling the distance between the electromagnetic wave irradiation device and the electric field control electrode to be constant. And electromagnetic waves from the electromagnetic wave irradiation device can be shielded by the air gap control member.
[0043]
Seventh means In the charging device of Any one of the first to sixth means A plurality of charging devices having the structure described above are arranged so that a wide range of the object to be charged can be charged at a time. With a single charging device, a wide range of the object to be charged can be uniformly charged at once. It was difficult, Any one of the first to sixth means By arranging a plurality of charging devices having the above-described configuration, a wide range of the object to be charged can be uniformly charged at once.
[0044]
Eighth means In the charging device of Seventh means In addition to the structure and effect of the electric field control electrode And gap control member Common to multiple charging devices In And The object to be charged In this way, a gap control member is arranged long in the longitudinal direction, and by sharing one control electrode among multiple charging devices in this way, wiring is simplified and the device is arrayed and assembled The process can be simplified, and further, the electromagnetic wave shielding effect by the air gap control member can be improved, and safety can be ensured.
[0045]
Ninth means In the charging device of 7th or 8th means Among the plurality of charging devices, the charging device on the charged object end side has a structure in which a gap control member is also provided on the end side. By providing the air gap control member also on the end side of the charging device on the end side of the charged body, the electromagnetic wave shielding effect by the air gap control member can be further improved, and safety can be ensured.
[0046]
Tenth means In the charging device of Any one of the first to ninth means In addition to the structure and effect of the above, the air gap control member is made of a material that hardly transmits electromagnetic waves, and has an effect as an electromagnetic wave shielding plate. Thus, the air gap control member is effective as an electromagnetic wave shielding plate. By adopting the configuration, leakage of electromagnetic waves to the outside can be prevented, and the safety of the apparatus can be further improved.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a configuration of a charging device according to an embodiment of the present invention.
FIG. 2 is a diagram showing the relationship between the height h of the electromagnetic wave irradiation device shown in FIG. 1 and the charging potential Vs of the electrostatic latent image carrier.
3 is an explanatory diagram of a main configuration of the charging device illustrated in FIG. 1, and is a diagram illustrating an example of an installation position and a shape of a space control member.
FIG. 4 is a configuration explanatory diagram of a charging device according to a second embodiment of the present invention.
FIG. 5 is a configuration explanatory view of a charging device showing a third embodiment of the present invention.
FIG. 6 is a configuration explanatory diagram of a charging device according to a fourth embodiment of the present invention.
[Explanation of symbols]
1: Electromagnetic wave irradiation device
2: Electrostatic latent image carrier (charged body)
2a: photosensitive layer
2b: Core metal
3: Grid electrode (electric field control electrode)
4, 4a, 4b, 4c, 4d, 4e, 4f: Gap control member
5, 6, 7: Power supply for bias application

Claims

An electromagnetic wave irradiation device and an electric field forming unit are provided. The electromagnetic wave irradiation device irradiates an electromagnetic wave to a space on the object to be charged and forms an electric field by the electric field forming unit, thereby charging the object to be charged to a desired potential Vs. a charging device for the said electromagnetic wave irradiating device controls the electric field by arranging a field control electrode between the charged member, integrally provided with a gap control member between the electromagnetic wave irradiation device and the field control electrode A plurality of charging devices configured to control the distance between the electromagnetic wave irradiation device and the electric field control electrode to be constant, and arranging the plurality of charging devices in the longitudinal direction of the object to be charged, It is configured so that it can be charged at one time, and among the plurality of charging devices, in the charging device on the end side in the longitudinal direction of the body to be charged, a gap control member is also provided on the end side. Charging feature Location.

An electromagnetic wave irradiation device and an electric field forming unit are provided. The electromagnetic wave irradiation device irradiates an electromagnetic wave to a space on the object to be charged and forms an electric field by the electric field forming unit, thereby charging the object to be charged to a desired potential Vs. A charging device for controlling the electric field by providing an electric field control electrode between the electromagnetic wave irradiation device and the object to be charged, and providing a gap control member between the electromagnetic wave irradiation device and the electric field control electrode. A plurality of charging devices configured to control the distance between the electromagnetic wave irradiation device and the electric field control electrode to be constant, and arranging the plurality of charging devices in the longitudinal direction of the object to be charged, configured so as to be charged at a time, and, and said gap controlling member and the field control electrode, while the common multiple of the charging device, were placed longitudinally long the gap control member of the member to be charged this A charging device according to claim.

3. The charging device according to claim 1, wherein the air gap control member is made of an insulator .

3. The charging device according to claim 1, wherein the electric field control electrode has a grid shape having a large number of openings .

4. The charging device according to claim 1, wherein the air gap control member is provided on the upstream side in the moving direction of the member to be charged.

4. The charging device according to claim 1, wherein the air gap control member is provided on the downstream side in the moving direction of the member to be charged.

In the charging device according to claim 1, wherein a charging device which is characterized by providing a gap controlling member on both the upstream and downstream sides of the member to be charged move direction.

8. The charging device according to claim 1, wherein the air gap control member is made of a member that does not easily transmit electromagnetic waves, and has an effect as an electromagnetic wave shielding plate .